Multi-phase high thermal conductivity composite dielectric materials

ABSTRACT

Disclosed herein are embodiments of materials having high thermal conductivity along with a high dielectric constants. In some embodiments, a two phase composite ceramic material can be formed having a contiguous aluminum oxide phase with a secondary phase embedded within the continuous phase. Example secondary phases include calcium titanate, strontium titanate, or titanium dioxide.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND Field

This disclosure generally relates to composite ceramic materials havinghigh thermal conductivity and a high dielectric constant.

Description of the Related Art

Many emerging applications for high dielectric materials require thedielectric material to be heated and cooled very rapidly during activeuse. This can lead to the possibility of thermal shock of the material,in particular when the heating and cooling is applied to monolithicpolycrystalline ceramic dielectrics. Thermal shock can occur when achange in temperature forms a thermal gradient on a material, which thencauses different portions of the material to expand or contract bydifferent amounts as compared with other portions of the material. Thisdifferential in the expansion of different portions of the material cancause increased stress and/or strain between the portions. If thestress/strain is too great, be it after repeated stress/strain or a highinitial stress/strain, cracks can form into the material. Eventually,the cracks can lead to structural failure of the material. Thus, thermalshock can physically damage the high dielectric material, making itunusable for its intended purpose. Moreover, thermal shock to thematerial can also lead to overall damage of components that the materialis incorporated into.

Further, applications requiring high power levels, such as certainlighting systems, require very high thermal conductivity materials inorder to function at their optimal levels. However, a significantproblem is that most high thermal conductivity ceramics are expensive,extremely toxic, and/or have low dielectric constants.

SUMMARY

Disclosed herein are embodiments of a dual-phase composite ceramicmaterial, the material comprising a primary phase, and at least onesecondary phase located within the primary phase forming a dual-phasecomposite, the dual-phase composite can have a dielectric constant ofgreater than 20 and a thermal conductivity of greater than 20 W·m⁻¹·K⁻¹.

In some embodiments, the primary phase can include aluminum oxide. Insome embodiments, the primary phase can be generally contiguous. In someembodiments, the dual-phase composite can have a dielectric constant ofgreater than 25. In some embodiments, the thermal conductivity can begreater than 30 W·m⁻¹·K⁻¹.

In some embodiments, the secondary phase can be generally non-reactivewith aluminum oxide. In some embodiments, the secondary phase caninclude more than one composition. In some embodiments, the secondaryphase can be selected from the group consisting of CaTiO₃, TiO₂, LaAlO₃,La₂MgTiO₆, YAlO₃, SmAlO₃, Mg₄Nb₂O₉, and La₄Ti₃O₁₂.

In some embodiments, the dual-phase composite can have a temperaturedrift of resonant frequency lower than 1000 ppm/Degree C. In someembodiments, the primary phase can include aluminum oxide and thesecondary phase includes a high dielectric constant material.

Also disclosed herein are embodiments of a method of forming adual-phase composite ceramic material, the method comprising mixingtogether materials that will form out a primary generally contiguousphase and a secondary non-contiguous phase, materials forming theprimary phase being generally non-reactive with materials forming thesecondary phase, and sintering the materials to form a composite ceramichaving the primary generally contiguous phase and the secondarynon-contiguous phase, the composite ceramic having a dielectric constantof greater than 20 and a thermal conductivity of greater than 20W·m⁻¹·K⁻¹.

In some embodiments, the primary phase can include aluminum oxide andthe secondary phase includes a metallic oxide. In some embodiments, thecomposite ceramic can have a thermal conductivity of greater than 30W·m⁻¹·K⁻¹. In some embodiments, the primary phase can include aluminumoxide and the secondary phase includes a high dielectric constantmaterial.

Also disclosed herein are embodiments of a radiofrequency componentformed from a ceramic material comprising a primary phase, the primaryphase being generally contiguous, and at least one secondary phaselocated within the primary phase forming a dual-phase composite, thedual-phase composite having a dielectric constant of greater than 20 anda thermal conductivity of greater than 20 W·m⁻¹·K⁻¹.

In some embodiments, the primary phase can include aluminum oxide andthe secondary phase is selected from the group consisting of CaTiO₃,TiO₂, LaAlO₃, La₂MgTiO₆, YAlO₃, SmAlO₃, Mg₄Nb₂O₉, and La₄Ti₃O₁₂. In someembodiments, the primary phase can include aluminum oxide and thesecondary phase includes a high dielectric constant material.

In some embodiments, the radiofrequency component can be incorporatedinto solid state lighting. In some embodiments, the radiofrequencycomponent can be incorporated into a cellular tower. In someembodiments, the radiofrequency component can be used at frequencies ofgreater than 100 MHz.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows how materials having one or more featuresdescribed herein can be designed, fabricated, and used.

FIGS. 2A-B illustrate structural overviews of embodiments of a compositematerial disclosed herein.

FIG. 3 illustrates an example process flow for making an embodiment of acomposite ceramic material having one or more features described herein.

FIG. 4 shows a process that can be implemented to fabricate a compositeceramic material having one or more features as described herein.

FIG. 5 shows a process that can be implemented to form a shaped objectfrom powder material described herein.

FIG. 6 shows examples of various stages of the process of FIG. 5.

FIG. 7 shows a process that can be implemented to sinter formed objectssuch as those formed in the example of FIGS. 5 and 6.

FIG. 8 shows examples of various stages of the process of FIG. 7.

FIG. 9 illustrates a telecommunication base station system incorporatingan embodiment of a composite ceramic material disclosed herein.

FIG. 10 illustrates an embodiment of a power amplifier module which canuse embodiments of the disclosed material.

FIG. 11 illustrates an embodiment of a wireless device which can useembodiments of the disclosed material.

FIG. 12 illustrates a perspective view of a cellular antenna basestation incorporating embodiments of the disclosure.

FIG. 13 illustrates housing components of a base station incorporatingembodiments of the disclosed material.

FIG. 14 illustrates a cavity filter used in a base station incorporatingembodiments of the material disclosed herein.

FIG. 15 illustrates an embodiment of a solid-state light bulbincorporating embodiments of the disclosed ceramic.

FIG. 16 illustrates an embodiment of a plurality of solid-state lightbulbs incorporating embodiments of the disclosed ceramic.

DETAILED DESCRIPTION

Disclosed herein are embodiments of ceramic materials and methods ofmanufacturing said materials which can have high thermal conductivity aswell as a high dielectric constant. In some embodiments, the ceramicmaterial can be formed as a composite material having multiple phases.In particular, a two-phase ceramic material can be formed, each of thephases having unique and advantageous properties to improve the overalltwo-phase ceramic material. The combination of the two phases can allowthe composite material to generally maintain, or improve, the highproperties achieved by each of the phases in the composite ceramicindividually. The properties achieved by embodiments of the disclosedcomposite ceramics can be advantageous for many different technologies,especially for radiofrequency (RF) applications in the high frequencyranges (>100 MHz) and cellular communications. Further, embodiments ofthe disclosed material can be used for solid-state lighting. Embodimentsof the materials can be further used for other applications, and theparticular application of the material is not limiting.

FIG. 1 schematically shows how one or more chemical elements (block 1),chemical compounds (block 2), chemical substances (block 3) and/orchemical mixtures (block 4) can be processed to yield one or morematerials (block 5) having one or more features described herein. Insome embodiments, such materials can be formed into ceramic materials(block 6) configured to include a desirable dielectric property (block7), a magnetic property (block 8) and/or an advanced material property(block 9).

In some embodiments, a material having one or more of the foregoingproperties can be implemented in applications (block 10) such asradio-frequency (RF) application. Such applications can includeimplementations of one or more features as described herein in devices12. In some applications, such devices can further be implemented inproducts 11. Examples of such devices and/or products are describedherein.

Dual-Phase Composite Ceramic Material

Composite materials, also known as composition materials or composites,are materials that can be formed from two or more constituent materials.Typically, the two or more materials have different physical,performance, and/or chemical properties. Once combined, the finalcomposite can have different physical, performance, and/or chemicalproperties than the individual constituent materials. In someembodiments, the individual constituent materials can remain separate inthe final composite material by forming separate phases.

Composite materials have a number of applications in the currentmaterials space. The can be used in mortars, concretes, plastics,metals, and ceramics. Discussed herein are embodiments of compositeceramic materials.

Useful materials for applications as disclosed herein are compositematerials. In some embodiments, a composite ceramic material can beformed out of two or more different phases which can be found in thesame material upon stabilization. In particular, the composite ceramiccan be formed from a first (or primary) phase, which can be onecontiguous phase, with particles/portions/sections of a secondary phase(and/or tertiary/quaternary/etc. phases) embedded within the contiguousphase, thereby creating a dual-phase composite material. In someembodiments, a third phase of material can be embedded into the firstphase, the second phase, both phases, or can cross the phases.

An example embodiment of such a dual-phase material is shown in FIGS.2A-2B. As shown in FIG. 2A, the composite ceramic material 200 can havea base primary phase material 202. Further, portions of secondary phasematerial 204 can be scattered throughout the primary phase material 202.FIG. 2B illustrates a more connected secondary phase material 204 ascompared to the embodiment of FIG. 2A. FIGS. 2A-B show just an exampleof a composite ceramic 200, and the particular location of the differentphases is not limiting. The primary phase can be generally contiguouswhereas the secondary phase can form isolated “islands” within theprimary phase. In some embodiments, there can be two dispersed secondphases existing within the primary phase. For example, they can beisolated from one another forming separate “islands” within the primaryphase. However, there is a statistical possibility of the two secondaryphases coming into contact with one another. In some cases, there may bea small reaction zone at the interface of the primary phase and one ormore of the secondary phases.

In some embodiments, the primary phase may not be fully contiguous asthe secondary phase may cut off portions of it due to various formationmethods. In some embodiments, the primary phase may be fully contiguous.In some embodiments, the primary phase may be fully contiguous over a1×1 inch, 2×2 inch, 3×3 inch, 4×4 inch, or 5×5 inch area. Further, thesecondary phase may be a number of different portions within the firstphase, or can be represented by a larger singular portion within thefirst phase.

The secondary phase can also be composed of a number of differentmaterials, and thus the secondary phase can form with some locationshaving material A whereas other locations can have material B orcombinations of both. In some embodiments, a location can be a majorityA and in other locations can be a majority B. In some embodiments, thesecondary phases can be identical to one another in structure orcomposition in some embodiments. In some embodiments, the secondaryphases may be generally the same with minor variations/impurities. Insome embodiments the secondary phases may act in generally the same oran identical manner while having compositional differences. It will beunderstood that while one of the phases is described as “secondary”, theparticular amount of the material forming the secondary phase may begreater than, equal to, or lower than the primary phase. The particularstructure of the final composite is not limiting.

Compositions for Embodiments of Dual-Phase Ceramic Materials

In some embodiments, the dual-phase ceramic materials can be partiallyor fully defined by its composition. Further, these compositions canlead to a particular microstructure formation, which can be used tofully or partially define the material. The dual-phase ceramic materialcan include two different ceramics, and may not include other materialssuch as metals or polymers/plastics.

In some embodiments, the use of aluminum oxide (Al₂O₃), such as alumina,has been shown to allow for advantageous properties to form in thedual-phase composite ceramic. Alumina and aluminum oxide can be usedinterchangeably herein. Alumina itself typically has a low dielectricconstant, 8 (or about 8), though it has very good thermal conductivity,30 W·m⁻¹·K⁻¹ (or about 30). Thus, aluminum oxide may be advantageous forthe base material and form the primary phase in a dual-phase compositematerial.

Accordingly, a two-phase ceramic material can be designed with aluminumoxide as the primary phase and particles of a second phase material witha higher dielectric constant can be incorporated into the aluminum oxideso as to create a material with a high dielectric constant and goodthermal conductivity. Thus the dispersed second phase can give thecomposite with alumina an overall higher dielectric constant than a purealuminum oxide ceramic. The dielectric constant and thermal conductivitycan be balanced to optimize the particular advantageous qualities of thematerial.

In some embodiments, other primary phase materials may be used as well.For example, spinels, such as MgAl₂O₄, Mg₂SiO₄ (forsterite), andcordierite can be used as the primary phase.

The second phase material may be, for example, calcium titanate,strontium titanate or titanium dioxide with other phases added to adjustthe temperature coefficient of the dielectric resonant frequency. Otherphases can include solid solutions based on calcium titanate, forexample Ca_(1−x)La_(2/3x)TiO₃. However, other materials can be used aswell, such as different compositions incorporating lanthanum aluminate,and the particular materials are not limiting. In particular, metallicoxides as a whole can provide advantageous properties to the aluminumoxide. In some embodiments, second phase materials can be highdielectric constant materials (e.g., >30) with the perovskite,orthorhombic tungsten bronze, alpha-lead oxide, or rutile structure.

By adding the secondary phase material with a high dielectric constantto aluminum oxide and creating a two phase composite with aluminum oxidebeing the contiguous phase, a high thermal conductivity compositeceramic with a dielectric constant of 20 or greater may be obtained. Insome embodiments, the dielectric constant can be 20 or greater (or about20 or greater), 25 or greater (or about 25 or greater), 30 or greater(or about 30 or greater), or 35 or greater (or about 35 or greater).

In some embodiments, the material may also still exhibit high thermalconductivity, thereby reducing thermal shock. For example, the thermalconductivity can be at least as high as that of aluminum oxide byitself. Thus, the secondary phases may not negatively, or at least maynot significantly negatively, affect the thermal conductivity of thematerial. In some embodiments, the thermal conductivity of the compositeceramic disclosed herein can be within 20% (or within about 20%), 10%(or within about 10%), 5% (or within about 5%), or 1% (or within about1%) of the thermal conductivity of alumina. In some embodiments, thethermal conductivity of embodiments of the disclosed material can be 20W·m⁻¹·K⁻¹ or greater (or about 20 W·m⁻¹·K⁻¹ or greater). In someembodiments, the thermal conductivity of embodiments of the disclosedmaterial can be 30 W·m⁻¹·K⁻¹ or greater (or about 30 W·m⁻¹·K⁻¹ orgreater). Thus, embodiments of the materials can be used during quickheating and cooling processes, as there is a lower possibility ofthermal shock.

In some embodiments, the composite material may have a lower temperaturedrift of resonant frequency (t_(F)). It can be advantageous to have alow t_(F) to avoid any change in dielectric constant as the material isheated. In some embodiments, the composite material can have atemperature drift of resonant frequency lower than 3000 ppm/Degree (orlower than about 3000 ppm/Degree), lower than 2000 ppm/Degree (or lowerthan about 2000 ppm/Degree), lower than 1000 ppm/Degree C. (or lowerthan about 1000 ppm/Degree).

Table I below illustrates compositions having a primary alumina phasewith different types of additive secondary phases of titanium oxide,wherein the secondary phase is only a single type of ceramic.

TABLE I Two Material Composite Ceramics and Their Properties Fired FiredWt. % Wt. % Firing Density Dielectric Alumina Additive additiveTemperature (g/cm³) Constant 33.2 CaTiO₃ 66.8 1400 3.94 70.89 33.2CaTiO₃ 66.8 1450 3.81 57.75 33.2 CaTiO₃ 66.8 1475 3.75 60.72 31 TiO₂69.0 1440 3.59 28.52 31 TiO₂ 69.0 1400 3.44 27.96 33.4 CaTiO₃ 66.6 13903.93 95.52 36.0 CaTiO₃ 64.0 1390 3.94 93.06 40.0 CaTiO₃ 60.0 1390 3.9385.97 43.0 CaTiO₃ 57.0 1390 3.95 80.80 47.0 CaTiO₃ 53.0 1390 3.95 73.7050.0 CaTiO₃ 50.0 1390 3.95 68.20 54.0 CaTiO₃ 46.0 1390 3.93 61.30 58.0CaTiO₃ 42.0 1390 3.94 54.70 55.0 CaTiO₃ 45.0 1390 3.93 54.86

As shown in the above table, very high levels of dielectric constant canbe formed. In fact, dielectric constants over 90 can be achieved.

Table II shows different compositions having alumina as the primarymaterial with multi-compositional secondary phase ceramics embeddedwithin the alumina.

TABLE II Three Material Composite Ceramics and Their PropertiesTemperature Fired Drift of Fired Wt. % Wt % Wt. % Wt % Firing Densityresonant Dielectric Alumina CaTiO₃ LaAlO₃ La₂MgTiO₆ Temp. (g/cm³)frequency (t_(F)) Constant 34 56 10 1390 4.11 +320.25 63.34 34 50 161390 4.15 +243.81 52.55 34 44 22 1390 4.16 +174.63 41.63 44 50 6 13904.03 +417.9 57.80 44 44 12 1390 4.11 +262.15 45.05 44 36 20 1390 4.1434.66 34 56 10 1390 4.05 +366.11 62.30 34 50 16 1390 4.13 +274.76 56.5134 44 22 1390 4.20 +180 47.39 44 50 6 1390 3.97 +399 52.39 44 44 12 13904.05 +268 45.02 44 36 20 1390 4.15 +175 40.40 34 50 16 1390 4.12 50.51

The secondary phases discussed in Table II can separate into separatephases (e.g., phases A, B, and C). As shown, dual-phase composites canagain achieve high dielectric constants, such as above 40, 50, or 60.

However, high dielectric constants may negatively affect the temperaturedrift of resonant frequency, meaning that as the material is heated up,the dielectric constant can drop off.

Table III shows different compositions having alumina as the primarymaterial with multi-compositional secondary phase ceramics embeddedwithin the alumina.

TABLE III Three Material Composite Ceramics and Their PropertiesTemperature Drift of resonant Fired Wt % Wt. % Wt % Firing frequencyDielectric Wt. % Alumina CaTiO₃ YAlO₃ SmAlO₃ Temperature (t_(F))Constant 34 56 10 1390 +201.62 71.22 44 50 6 1390 +298 46.78 34 56 101390 +322 57.65 34 50 16 1390 +171.7 44.51 34 44 22 1390 +100.11 35.5844 50 6 1390 +397.96 54.69 44 44 12 1390 +198 39.83 44 36 20 1390 +75.9928.55 50 40 10 1390 +130.81 36.67 40 47 13 1390 +196.53 42.69 44 41 151390 +193.94 34.80

The secondary phases discussed in Table II can separate into separatephases (e.g., phases A, B, and C). Once again, high dielectric constantcomposite materials can be formed.

Table IV shows different compositions having alumina as the contiguousprimary material with multi-compositional secondary phase ceramicsembedded within the alumina.

TABLE IV Three Material Composite Ceramics and Their PropertiesTemperature Drift of Fired Wt. % Wt % Wt. % Wt % Firing resonantDielectric Alumina CaTiO₃ LaAlO₃ Other Temperature frequency (t_(F))Constant 44 36 20 1390 +169.82 34.1 40 36 20 4% Mg₄Nb₂O₉ 1390 +125.7832.35 36 36 20 8% Mg₄Nb₂O₉ 1390 +177.33 34.29 44 36 16 4% Mg₄Nb₂O₉ 1390+164.18 36.34 40 36 16 8% Mg₄Nb₂O₉ 1390 +115.82 30.87 44 36 18 2%La₄Ti₃O₁₂ 1390 +156.97 34.53 44 36 16 4% La₄Ti₃O₁₂ 1390 +151.4 34.94 4836 14 2% La₄Ti₃O₁₂ 1390 +172.42 34.98 48 36 12 4% La₄Ti₃O₁₂ 1390 +167.235.24 44 36 20% SmAlO₃ 1390 +66.62 27.95 40 36 20% SmAlO₃ + 1390 +81.9628.71 4% Mg₄Nb₂O₉ 36 36 20% SmAlO₃ + 1390 +91.82 29.08 8% Mg₄Nb₂O₉ 44 3616% SmAlO₃ + 1390 +108.97 31.81 4% Mg₄Nb₂O₉ 40 36 16% SmAlO₃ + 1390+103.27 32.65 8% Mg₄Nb₂O₉

The secondary phases discussed in Table II can separate into separatephases (e.g., phases A, B, and C). As above, the materials disclosed inthe above table can have high dielectric constants, such as above about27, 28, 29, 30, 31, 32, 33, 34, and 35.

Preparation of the Composite Ceramic Materials:

The preparation of embodiments of the above-discussed compositematerials can be accomplished by using known ceramic techniques. Aparticular example of the process flow is illustrated in FIG. 3.

As shown in FIG. 3, the process begins with step 106 for weighing theraw material. The raw material may include oxides and carbonates such asAl₂O₃, CaTiO₃, TiO₂, LaAlO₃, La₂MgTiO₆, YAlO₃, SmAlO₃, Mg₄Nb₂O₉,La₄Ti₃O₁₂, or combinations thereof. In addition, organic based materialsmay be used in a sol gel process for ethoxides and/or acrylates orcitrate based techniques may be employed. Other known methods in the artsuch as co-precipitation of hydroxides, sol-gel, or laser ablation mayalso be employed as a method to obtain the materials. The amount andselection of raw material depends on the specific formulation.

After the raw materials are weighed, they are blended in Step 108 usingmethods consistent with the current state of the ceramic art, which caninclude aqueous blending using a mixing propeller, or aqueous blendingusing a vibratory mill with steel or zirconia media. In someembodiments, a glycine nitrate or spray pyrolysis technique may be usedfor blending and simultaneously reacting the raw materials.

The blended oxide is subsequently dried in Step 110, which can beaccomplished by pouring the slurry into a pane and drying in an oven,preferably between 100-400° C. or by spray drying, or by othertechniques known in the art.

The dried oxide blend is processed through a sieve in Step 112, whichhomogenizes the powder and breaks up soft agglomerates that may lead todense particles after calcining.

The material is subsequently processed through a pre-sintering calciningin Step 114. Preferably, the material is loaded into a container such asan alumina or cordierite sagger and heat treated in the range of about800-1600° C.

After calcining, the material is milled in Step 116, preferably in avibratory mill, an attrition mill, a jet mill or other standardcomminution technique to reduce the median particle size into the rangeof about 0.1 to 10.0 microns, though in some embodiments larger orsmaller sizes may be used as well. Milling is preferably done in a waterbased slurry but may also be done in ethyl alcohol or another organicbased solvent.

The material is subsequently spray dried in Step 118. During the spraydrying process, organic additives such as binders and plasticizers canbe added to the slurry using techniques known in the art. The materialis spray dried to provide granules amenable to pressing, preferably inthe range of about 10 microns to 150 microns in size.

The spray dried granules are subsequently pressed in Step 120,preferably by uniaxial or isostatic pressing to achieve a presseddensity to as close to 60% of the x-ray theoretical density as possible.In addition, other known methods such as tape casting, tape calendaringor extrusion may be employed as well to form the unfired body.

The pressed material is subsequently processed through a calciningprocess in Step 122. Preferably, the pressed material is placed on asetter plate made of material such as alumina which does not readilyreact with the garnet material. The setter plate is heated in a periodickiln or a tunnel kiln in air or pressure oxygen in the range of betweenabout 850° C.-1600° C. to obtain a dense ceramic compact. Other knowntreatment techniques, such as induction heat, hot pressing, fast firing,or assisted fast firing, may also be used in this step. In someembodiments, a density having >98% of the theoretical density can beachieved.

The dense ceramic compact is machined in the Step 124 to achievedimensions suitable or the particular applications.

Fabrication of Radiofrequency Devices

FIGS. 4-8 show examples of how radiofrequency devices having one or morefeatures as described herein can be fabricated. FIG. 4 shows a process20 that can be implemented to fabricate a ceramic material having one ormore of the foregoing properties. In block 21, powder can be prepared.In block 22, a shaped object can be formed from the prepared powder. Inblock 23, the formed object can be sintered. In block 24, the sinteredobject can be finished to yield a finished ceramic object having one ormore desirable properties.

In implementations where the finished ceramic object is part of adevice, the device can be assembled in block 25. In implementationswhere the device or the finished ceramic object is part of a product,the product can be assembled in block 26.

FIG. 4 further shows that some or all of the steps of the exampleprocess 20 can be based on a design, specification, etc. Similarly, someor all of the steps can include or be subjected to testing, qualitycontrol, etc.

In some implementations, the powder preparation step (block 21) of FIG.4 can be performed by the example process described in reference to FIG.3. Powder prepared in such a manner can include one or more propertiesas described herein, and/or facilitate formation of ceramic objectshaving one or more properties as described herein.

In some implementations, powder prepared as described herein can beformed into different shapes by different forming techniques. By way ofexamples, FIG. 5 shows a process 50 that can be implemented topress-form a shaped object from a powder material prepared as describedherein. In block 52, a shaped die can be filled with a desired amount ofthe powder. In FIG. 6, configuration 60 shows the shaped die as 61 thatdefines a volume 62 dimensioned to receive the powder 63 and allow suchpower to be pressed. In block 53, the powder in the die can becompressed to form a shaped object. Configuration 64 shows the powder inan intermediate compacted form 67 as a piston 65 is pressed (arrow 66)into the volume 62 defined by the die 61. In block 54, pressure can beremoved from the die. In block 55, the piston (65) can be removed fromthe die (61) so as to open the volume (62). Configuration 68 shows theopened volume (62) of the die (61) thereby allowing the formed object 69to be removed from the die. In block 56, the formed object (69) can beremoved from the die (61). In block 57, the formed object can be storedfor further processing.

In some implementations, formed objects fabricated as described hereincan be sintered to yield desirable physical properties as ceramicdevices. FIG. 7 shows a process 70 that can be implemented to sintersuch formed objects. In block 71, formed objects can be provided. Inblock 72, the formed objects can be introduced into a kiln. In FIG. 8, aplurality of formed objects 69 are shown to be loaded into a sinteringtray 80. The example tray 80 is shown to define a recess 83 dimensionedto hold the formed objects 69 on a surface 82 so that the upper edge ofthe tray is higher than the upper portions of the formed objects 69.Such a configuration allows the loaded trays to be stacked during thesintering process. The example tray 80 is further shown to definecutouts 83 at the side walls to allow improved circulation of hot gas atwithin the recess 83, even when the trays are stacked together. FIG. 8further shows a stack 84 of a plurality of loaded trays 80. A top cover85 can be provided so that the objects loaded in the top tray generallyexperience similar sintering condition as those in lower trays.

In block 73, heat can be applied to the formed objects so as to yieldsintered objects. Such application of heat can be achieved by use of akiln. In block 74, the sintered objects can be removed from the kiln. InFIG. 8, the stack 84 having a plurality of loaded trays is depicted asbeing introduced into a kiln 87 (stage 86 a). Such a stack can be movedthrough the kiln (stages 86 b, 86 c) based on a desired time andtemperature profile. In stage 86 d, the stack 84 is depicted as beingremoved from the kiln so as to be cooled.

In block 75, the sintered objects can be cooled. Such cooling can bebased on a desired time and temperature profile. In block 206, thecooled objects can undergo one or more finishing operations. In block207, one or more tests can be performed.

Heat treatment of various forms of powder and various forms of shapedobjects are described herein as calcining, firing, annealing, and/orsintering. It will be understood that such terms may be usedinterchangeably in some appropriate situations, in context-specificmanners, or some combination thereof.

Application of the Material

One or more embodiments of the disclosed composite ceramic can provide aframework to develop real world devices in the field of electronics,including, but not limited to, radiofrequency (or RF). Electroniccomponents used in radio frequency preferably have improved Q, a highdielectric constant, high thermal conductivity, and a temperaturecoefficient of resonant frequency near 0. Embodiments of the disclosedcomposite ceramic can provide for a ceramic material having suchadvantageous qualities. In some embodiments, the material can be usedfor any high power device that is susceptible to rapid heating where ahigh dielectric constant ceramic is used.

Embodiments of the composite ceramics can have applications inelectronic devices and can be incorporated into numerous types of RFdevices including antennas, transformers, inductors, and circulators.

FIG. 9 illustrates a telecommunication base station system 500comprising a transceiver 502, a synthesizer 504, an RX filter 506, a TXfilter 508, and magnetic isolators 510 and an antenna 512. The magneticisolators 510 can be incorporated in a single channel PA and connectorpad, integrated triplate or microstrip drop-in. In preferredimplementations, the magnetic isolators 510 comprise an embodiment ofthe disclosed composite ceramic.

FIGS. 10 and 11 respectively illustrate a power amplifier module 1010and wireless device 1011 which can include one or more radio frequencydevices implemented using any of the methods, materials, and devices ofthe present disclosure. For instance, the power amplifier module 1010and the wireless device 1011 can include one or more antennas,transformers, inductors, circulators, absorbers, or other RF devices orother devices implemented according to the present disclosure, includingdevices incorporating an embodiment of the disclosed composite ceramic.

FIG. 10 is a schematic diagram of a power amplifier module (PAM) 1010for amplifying a radio frequency (RF) signal. The illustrated poweramplifier module 1010 amplifies an RF signal (RF_IN) to generate anamplified RF signal (RF_OUT).

FIG. 11 is a schematic block diagram of an example wireless or mobiledevice 1011. The example wireless device 1011 depicted in FIG. 11 canrepresent a multi-band and/or multi-mode device such as amulti-band/multi-mode mobile phone. By way of examples, Global Systemfor Mobile (GSM) communication standard is a mode of digital cellularcommunication that is utilized in many parts of the world. GSM modemobile phones can operate at one or more of four frequency bands: 850MHz (approximately 824-849 MHz for Tx, 869-894 MHz for Rx), 900 MHz(approximately 880-915 MHz for Tx, 925-960 MHz for Rx), 1800 MHz(approximately 1710-1785 MHz for Tx, 1805-1880 MHz for Rx), and 1900 MHz(approximately 1850-1910 MHz for Tx, 1930-1990 MHz for Rx). Variationsand/or regional/national implementations of the GSM bands are alsoutilized in different parts of the world.

Code division multiple access (CDMA) is another standard that can beimplemented in mobile phone devices. In certain implementations, CDMAdevices can operate in one or more of 800 MHz, 900 MHz, 1800 MHz and1900 MHz bands, while certain W-CDMA and Long Term Evolution (LTE)devices can operate over, for example, 22 or more radio frequencyspectrum bands.

One or more features of the present disclosure can be implemented in theforegoing example modes and/or bands, and in other communicationstandards. For example, 802.11, 2G, 3G, 4G, LTE, and Advanced LTE arenon-limiting examples of such standards. To increase data rates, thewireless device 1011 can operate using complex modulated signals, suchas 64 QAM signals.

In certain embodiments, the wireless device 1011 can include switches1012, a transceiver 1013, an antenna 1014, power amplifiers 1017 a, 1017b, a control component 1018, a computer readable medium 1019, aprocessor 1020, a battery 1021, and a power management system 1030, anyof which can include embodiments of the disclosed material.

The transceiver 1013 can generate RF signals for transmission via theantenna 1014. Furthermore, the transceiver 1013 can receive incoming RFsignals from the antenna 1014.

It will be understood that various functionalities associated with thetransmission and receiving of RF signals can be achieved by one or morecomponents that are collectively represented in FIG. 11 as thetransceiver 1013. For example, a single component can be configured toprovide both transmitting and receiving functionalities. In anotherexample, transmitting and receiving functionalities can be provided byseparate components.

Similarly, it will be understood that various antenna functionalitiesassociated with the transmission and receiving of RF signals can beachieved by one or more components that are collectively represented inFIG. 11 as the antenna 1014. For example, a single antenna can beconfigured to provide both transmitting and receiving functionalities.In another example, transmitting and receiving functionalities can beprovided by separate antennas. In yet another example, different bandsassociated with the wireless device 1011 can operate using differentantennas.

In FIG. 11, one or more output signals from the transceiver 1013 aredepicted as being provided to the antenna 1014 via one or moretransmission paths 1015. In the example shown, different transmissionpaths 1015 can represent output paths associated with different bandsand/or different power outputs. For instance, the two example poweramplifiers 1017 a, 1017 b shown can represent amplifications associatedwith different power output configurations (e.g., low power output andhigh power output), and/or amplifications associated with differentbands. Although FIG. 11 illustrates a configuration using twotransmission paths 1015 and two power amplifiers 1017 a, 1017 b, thewireless device 1011 can be adapted to include more or fewertransmission paths 1015 and/or more or fewer power amplifiers.

In FIG. 11, one or more detected signals from the antenna 1014 aredepicted as being provided to the transceiver 1013 via one or morereceiving paths 1016. In the example shown, different receiving paths1016 can represent paths associated with different bands. For example,the four example receiving paths 1016 shown can represent quad-bandcapability that some wireless devices are provided with. Although FIG.11 illustrates a configuration using four receiving paths 1016, thewireless device 1011 can be adapted to include more or fewer receivingpaths 1016.

To facilitate switching between receive and transmit paths, the switches1012 can be configured to electrically connect the antenna 1014 to aselected transmit or receive path. Thus, the switches 1012 can provide anumber of switching functionalities associated with operation of thewireless device 1011. In certain embodiments, the switches 1012 caninclude a number of switches configured to provide functionalitiesassociated with, for example, switching between different bands,switching between different power modes, switching between transmissionand receiving modes, or some combination thereof. The switches 1012 canalso be configured to provide additional functionality, includingfiltering and/or duplexing of signals.

FIG. 11 shows that in certain embodiments, a control component 1018 canbe provided for controlling various control functionalities associatedwith operations of the switches 1012, the power amplifiers 1017 a, 1017b, the power management system 1030, and/or other operating components.

In certain embodiments, a processor 1020 can be configured to facilitateimplementation of various processes described herein. The processor 1020can implement various computer program instructions. The processor 1020can be a general purpose computer, special purpose computer, or otherprogrammable data processing apparatus.

In certain embodiments, these computer program instructions may also bestored in a computer-readable memory 1019 that can direct the processor1020 to operate in a particular manner, such that the instructionsstored in the computer-readable memory 1019.

The illustrated wireless device 1011 also includes the power managementsystem 1030, which can be used to provide power amplifier supplyvoltages to one or more of the power amplifiers 1017 a, 1017 b. Forexample, the power management system 1030 can be configured to changethe supply voltages provided to the power amplifiers 1017 a, 1017 b toimprove efficiency, such as power added efficiency (PAE). The powermanagement system 1030 can be used to provide average power tracking(APT) and/or envelope tracking (ET). Furthermore, as will be describedin detail further below, the power management system 1030 can includeone or more low dropout (LDO) regulators used to generate poweramplifier supply voltages for one or more stages of the power amplifiers1017 a, 1017 b. In the illustrated implementation, the power managementsystem 1030 is controlled using a power control signal generated by thetransceiver 1013. In certain configurations, the power control signal isprovided by the transceiver 1013 to the power management system 1030over an interface, such as a serial peripheral interface (SPI) or MobileIndustry Processor Interface (MIPI).

In certain configurations, the wireless device 1011 may operate usingcarrier aggregation. Carrier aggregation can be used for both FrequencyDivision Duplexing (FDD) and Time Division Duplexing (TDD), and may beused to aggregate a plurality of carriers or channels, for instance upto five carriers. Carrier aggregation includes contiguous aggregation,in which contiguous carriers within the same operating frequency bandare aggregated. Carrier aggregation can also be non-contiguous, and caninclude carriers separated in frequency within a common band or indifferent bands.

As mentioned above, circuits and devices having one or more features asdescribed herein can be implemented in RF applications such as awireless base-station. Such a wireless base-station can include one ormore antennas configured to facilitate transmission and/or reception ofRF signals. Such antenna(s) can be coupled to circuits and deviceshaving one or more circulators/isolators as described herein.

Thus, in some embodiments, the above disclosed material can beincorporated into different components of a telecommunication basestation, such as used for cellular networks and wireless communications.An example perspective view of a base station 2000 is shown in FIG. 12,including both a cell tower 2002 and electronics building 2004. This caninclude the components discussed above with respect to FIG. 9. The celltower 2002 can include a number of antennas 2006, typically facingdifferent directions for optimizing service, which can be used to bothreceive and transmit cellular signals while the electronics building2004 can hold electronic components such as filters, amplifiers, etc.discussed below. Both the antennas 2006 and electronic components canincorporate embodiments of the disclosed ceramic materials.

FIG. 13 illustrates hardware 2010 that can be used in the electronicsbuilding 2004, and can include the components discussed above. Forexample, the hardware 2010 can be a base station subsystem (BSS), whichcan handle traffic and signaling for the mobile systems.

FIG. 14 illustrates a further detailing of the hardware 2010 discussedabove. Specifically, FIG. 14 depicts a cavity filter/combiner 2020 whichcan be incorporated into the base station. The cavity filter 2020 caninclude, for example, bandpass filters such as those incorporatingembodiments of the disclosed material, and can allow the output of twoor more transmitters on different frequencies to be combined.

In some embodiments, the materials disclosed herein can be incorporatedinto solid-state lighting (SSL). Typical SSLs can incorporate differenttypes of light-emitting diodes for the production of light, such assemiconductor light-emitting diodes (LEDs), organic light-emittingdiodes (OLEDs) or polymer light-emitting diodes (PLEDs). SSLs canprovide advantages over other types of lighting systems such aselectrical filaments, plasma, or gas. For example, SSLs can haveimproved lifetime, improved energy savings, better quality of light,improved safety, and improved durability.

FIG. 15 illustrates an embodiment of an SSL light bulb 3000 which canincorporate the above-disclosed ceramics. As shown, the light bulb 3000can include a base connector 3002 for providing electricity to the lightbulb 3000. Further, the light bulb 3000 can include a housing 3004attached, either permanently or reversibly, from the base connector3002. In some embodiments, the housing 3004 can include a clear,partially clear, colored, etc. top 3006 where light can be directed.Inside the housing 3004 can be one or more LEDs 3008 which can providethe light for the light bulb 3000.

FIG. 16 illustrates and example application of the light bulb 3000 as,for example, a hanging light setup 3500. As shown in the figure, aplurality of light bulbs 3000 can be incorporated into a substrate 3010.In some embodiments, the light bulbs 3000 can be electrically connected,either in series or in parallel, to provide additional light.

In some embodiments, SSLs incorporating the disclosed ceramics can beused in a number of different applications, such as lightbulbs, trafficlights, vehicle lights, street/parking lights, buildings (exterior andinterior), remote controls, as well as other applications. Theparticular SSL application is not limiting.

From the foregoing description, it will be appreciated that inventivecomposite ceramics having advantageous properties and method ofmanufacturing are disclosed. While several components, techniques andaspects have been described with a certain degree of particularity, itis manifest that many changes can be made in the specific designs,constructions and methodology herein above described without departingfrom the spirit and scope of this disclosure.

Certain features that are described in this disclosure in the context ofseparate implementations can also be implemented in combination in asingle implementation. Conversely, various features that are describedin the context of a single implementation can also be implemented inmultiple implementations separately or in any suitable subcombination.Moreover, although features may be described above as acting in certaincombinations, one or more features from a claimed combination can, insome cases, be excised from the combination, and the combination may beclaimed as any subcombination or variation of any subcombination.

Moreover, while methods may be depicted in the drawings or described inthe specification in a particular order, such methods need not beperformed in the particular order shown or in sequential order, and thatall methods need not be performed, to achieve desirable results. Othermethods that are not depicted or described can be incorporated in theexample methods and processes. For example, one or more additionalmethods can be performed before, after, simultaneously, or between anyof the described methods. Further, the methods may be rearranged orreordered in other implementations. Also, the separation of varioussystem components in the implementations described above should not beunderstood as requiring such separation in all implementations, and itshould be understood that the described components and systems cangenerally be integrated together in a single product or packaged intomultiple products. Additionally, other implementations are within thescope of this disclosure.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include or do not include, certain features, elements,and/or steps. Thus, such conditional language is not generally intendedto imply that features, elements, and/or steps are in any way requiredfor one or more embodiments.

Conjunctive language such as the phrase “at least one of X, Y, and Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to convey that an item, term, etc. may beeither X, Y, or Z. Thus, such conjunctive language is not generallyintended to imply that certain embodiments require the presence of atleast one of X, at least one of Y, and at least one of Z.

Language of degree used herein, such as the terms “approximately,”“about,” “generally,” and “substantially” as used herein represent avalue, amount, or characteristic close to the stated value, amount, orcharacteristic that still performs a desired function or achieves adesired result. For example, the terms “approximately”, “about”,“generally,” and “substantially” may refer to an amount that is withinless than or equal to 10% of, within less than or equal to 5% of, withinless than or equal to 1% of, within less than or equal to 0.1% of, andwithin less than or equal to 0.01% of the stated amount. If the statedamount is 0 (e.g., none, having no), the above recited ranges can bespecific ranges, and not within a particular % of the value. Forexample, within less than or equal to 10 wt./vol. % of, within less thanor equal to 5 wt./vol. % of, within less than or equal to 1 wt./vol. %of, within less than or equal to 0.1 wt./vol. % of, and within less thanor equal to 0.01 wt./vol. % of the stated amount.

Some embodiments have been described in connection with the accompanyingdrawings. The figures are drawn to scale, but such scale should not belimiting, since dimensions and proportions other than what are shown arecontemplated and are within the scope of the disclosed inventions.Distances, angles, etc. are merely illustrative and do not necessarilybear an exact relationship to actual dimensions and layout of thedevices illustrated. Components can be added, removed, and/orrearranged. Further, the disclosure herein of any particular feature,aspect, method, property, characteristic, quality, attribute, element,or the like in connection with various embodiments can be used in allother embodiments set forth herein. Additionally, it will be recognizedthat any methods described herein may be practiced using any devicesuitable for performing the recited steps.

While a number of embodiments and variations thereof have been describedin detail, other modifications and methods of using the same will beapparent to those of skill in the art. Accordingly, it should beunderstood that various applications, modifications, materials, andsubstitutions can be made of equivalents without departing from theunique and inventive disclosure herein or the scope of the claims.

What is claimed is:
 1. A multi-phase composite ceramic material, thematerial comprising: a primary phase of aluminum oxide; a firstsecondary phase of CaTiO₃ located within the primary phase; and a secondsecondary phase of LaAlO₃ located within the primary phase, the firstsecondary phase and the second secondary phase forming a multi-phasecomposite, the multi-phase composite having a dielectric constant ofgreater than 20 and a thermal conductivity of greater than 20 W·m⁻¹·K⁻¹.2. The multi-phase composite ceramic material of claim 1 wherein theprimary phase is generally contiguous.
 3. The multi-phase compositeceramic material of claim 1 wherein the multi-phase composite has adielectric constant of greater than
 25. 4. The multi-phase compositeceramic material of claim 1 wherein the thermal conductivity is greaterthan 30 W·m⁻¹·K⁻¹.
 5. The multi-phase composite ceramic material ofclaim 1 wherein the multi-phase composite has a temperature drift ofresonant frequency lower than 1000 ppm/Degree C.
 6. A multi-phasecomposite ceramic material, the material comprising: an aluminum oxidephase; a first secondary phase of CaTiO₃ located within the aluminumoxide phase; and a second secondary phase of La₂MgTiO₆ located withinthe aluminum oxide phase forming a multi-phase composite, themulti-phase composite having a dielectric constant of greater than 20and a thermal conductivity of greater than 30 W·m⁻¹·K⁻¹.
 7. Amulti-phase composite ceramic material comprising at a generallycontiguous primary phase of aluminum oxide and a plurality of secondaryphases, a first of the plurality of secondary phases being CaTiO₃ and asecond of the plurality of secondary phases being selected from thegroup consisting of LaAlO₃, La₂MgTiO₆, YAlO₃, SmAlO₃, Mg₄Nb₂O₉, andLa₄Ti₃O₁₂, the plurality of secondary phases embedded within the primaryphase to form a multi-phase composite ceramic material having adielectric constant of greater than
 20. 8. The multi-phase compositeceramic material of claim 7 wherein the multi-phase composite ceramicmaterial has a thermal conductivity of greater than 20 W·m⁻¹·K⁻¹.
 9. Themulti-phase composite ceramic material of claim 6 wherein the aluminumoxide phase is generally contiguous.
 10. The multi-phase compositeceramic material of claim 6 wherein the multi-phase composite ceramicmaterial has a dielectric constant of greater than
 25. 11. Themulti-phase composite ceramic material of claim 6 wherein themulti-phase composite ceramic material has a dielectric constant ofgreater than
 35. 12. The multi-phase composite ceramic material of claim6 wherein the multi-phase composite ceramic material has a temperaturedrift of resonant frequency lower than 1000 ppm/Degree C.
 13. Themulti-phase composite ceramic material of claim 7 wherein themulti-phase composite ceramic material has a thermal conductivity ofgreater than 30 W·m⁻¹·K⁻¹.
 14. The multi-phase composite ceramicmaterial of claim 7 wherein the primary phase is contiguous.
 15. Themulti-phase composite ceramic material of claim 7 wherein themulti-phase composite ceramic material has a dielectric constant ofgreater than
 25. 16. The multi-phase composite ceramic material of claim1 wherein the multi-phase composite ceramic material has a dielectricconstant of greater than
 35. 17. The multi-phase composite ceramicmaterial of claim 1 further including Mg₄Nb₂O₉.
 18. The multi-phasecomposite ceramic material of claim 1 further including La₄Ti₃O₁₂. 19.The multi-phase composite ceramic material of claim 7 wherein theceramic material includes YAlO₃.
 20. The multi-phase composite ceramicmaterial of claim 7 wherein the ceramic material includes SmAlO₃.